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authorMikulas Patocka <mpatocka@redhat.com>2018-12-06 17:41:22 +0100
committerJens Axboe <axboe@kernel.dk>2018-12-10 16:30:38 +0100
commit6f75723190d88e1319bea623bfe0292bf3917965 (patch)
tree153b2c344577a6b14ab51726f3aa4ae11934795b /drivers/md/dm.c
parentblock: return just one value from part_in_flight (diff)
downloadlinux-6f75723190d88e1319bea623bfe0292bf3917965.tar.xz
linux-6f75723190d88e1319bea623bfe0292bf3917965.zip
dm: remove the pending IO accounting
Remove the "pending" atomic counters, that duplicate block-core's in_flight counters, and update md_in_flight() to look at percpu in_flight counters. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c34
1 files changed, 15 insertions, 19 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 33100e536c4e..70568f8b6c53 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -646,25 +646,30 @@ static void free_tio(struct dm_target_io *tio)
bio_put(&tio->clone);
}
-int md_in_flight(struct mapped_device *md)
+static bool md_in_flight(struct mapped_device *md)
{
- return atomic_read(&md->pending[READ]) +
- atomic_read(&md->pending[WRITE]);
+ int cpu;
+ struct hd_struct *part = &dm_disk(md)->part0;
+
+ for_each_possible_cpu(cpu) {
+ if (part_stat_local_read_cpu(part, in_flight[0], cpu) ||
+ part_stat_local_read_cpu(part, in_flight[1], cpu))
+ return true;
+ }
+
+ return false;
}
static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
- int rw = bio_data_dir(bio);
io->start_time = jiffies;
generic_start_io_acct(md->queue, bio_op(bio), bio_sectors(bio),
&dm_disk(md)->part0);
- atomic_inc(&md->pending[rw]);
-
if (unlikely(dm_stats_used(&md->stats)))
dm_stats_account_io(&md->stats, bio_data_dir(bio),
bio->bi_iter.bi_sector, bio_sectors(bio),
@@ -676,8 +681,6 @@ static void end_io_acct(struct dm_io *io)
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
unsigned long duration = jiffies - io->start_time;
- int pending;
- int rw = bio_data_dir(bio);
generic_end_io_acct(md->queue, bio_op(bio), &dm_disk(md)->part0,
io->start_time);
@@ -687,16 +690,11 @@ static void end_io_acct(struct dm_io *io)
bio->bi_iter.bi_sector, bio_sectors(bio),
true, duration, &io->stats_aux);
- /*
- * After this is decremented the bio must not be touched if it is
- * a flush.
- */
- pending = atomic_dec_return(&md->pending[rw]);
- pending += atomic_read(&md->pending[rw^0x1]);
-
/* nudge anyone waiting on suspend queue */
- if (!pending)
- wake_up(&md->wait);
+ if (unlikely(waitqueue_active(&md->wait))) {
+ if (!md_in_flight(md))
+ wake_up(&md->wait);
+ }
}
/*
@@ -1915,8 +1913,6 @@ static struct mapped_device *alloc_dev(int minor)
if (!md->disk)
goto bad;
- atomic_set(&md->pending[0], 0);
- atomic_set(&md->pending[1], 0);
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);